Fish population estimates were collected by electro fishing and rotenone from 102 coldwater streams within northern Sierra Nevada. A mean late summer standing crop of 41 lbs./acre or 224 adult trout per mile was computed. The mean trout biomass of streams decreased as stream width increased. Stream gradient appears to have an influence on fish species composition. Trout seemed to be most abundant in stream sections with gradients of over 150 feet per mile while nongame species were most abundant in the streams with gradients of less than 100 feet/mile. Brown trout (Salmo trutta) dominance occurred most frequently in stream sections with gradients of less than l00 feet/mile. Meadow streams contained the greatest trout densities while canyon streams had the lowest. Medium gradient forested streams were intermediate in productivity. Some 46% of the 102 streams sampled contained one or more species of nongame fish. Although populations as great as 400 lbs./acre were encountered, two-thirds of the nongame fish waters contained populations of less than 50 lbs./acre. Using biomass and yield information developed from typical California streams, the State?s 18,000 miles of trout streams could be expected to yield a maximum harvest of about 5 million wild trout annually. Since the estimated catch has approached this level, stream angling for wild trout in California appears to have reached the saturation point.
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